Colors don't bleed much these days. Some might, e.g. on handmade clothing such as tyedye but most commercial colors don't.

If you wash items of different weights, fabrics, etc. together the load can get unbalanced more easily. Such as as single heavy towel or jacket in with a bunch of light synthetic items.

The "towels" setting uses warmer water and faster spin speed but an overall shorter cycle (at least on my washer) compared to the "normal" cycle. This probably presumes that towels usually are made of cotton and aren't very dirty.

I agree that a fully manual mode would be nice. My washer (LG) doesn't have that but by knowing what the various cycles and optional settings (e.g. soil level, extra rinse) do you can get pretty close to what you want.

It depends. My clothing doesn't (typically) need to tumble for long whereas towels might and bedding needs to go for much longer. In general it's probably better for fabric to be washed for less time if possible. It wears out.

Also if you pay close attention you'll notice that things don't come fully clean (old machines didn't either) just "clean enough". Throw some well used dog bedding in with your shirts and this fact might become more readily noticable. So it makes sense to wash like-use with like-use for that reason alone.

The TC5 is fine by me. I've never had a washer that worked this well. The noise level is the last thing I'm worried about when a meaningful cycle completes within 30 minutes.

Actually old top loaders aren't so far off of that number. Maybe 40+ gallons per load.

But still I'm inclined to agree with the general sentiment of not micro optimizing things in ways that make people's lives more difficult.